The President and other American officials routinely take an oath to preserve, protect, and defend the Constitution. And although it is doubtful whether taking that oath has much (or any) effect on the actions of the officials who take it, the oath is a good reminder of the fact that constitutions are not self-enforcing. Constitutions themselves are mere words, written on mere paper, and can only achieve their purposes, whatever those purposes might be, with the supportive and enforcing efforts of actual human beings.

Citation
Frederick Schauer, Guarding the Guardians (reviewing Lars Vinx, translator & editor, The Guardians of the Constitution: Hans Kelsen and Carl Schmitt on the Limits of Constitutional Law) New Rambler (2016).
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